ABSTRACT
Background Stromal-derived factor 1α /chemokine receptor 4(SDF-1α/CXCR4) axis is one of the important signals which mediates several different activities such as chemotaxis,adhesion,proliferation and survival resulting in recruitment to sites of immune and inflammatory reactions.Considerable evidence suggests that CXCR4/SDF-1α axis is involved in tumor angiogenesis and plays a key role in the development of ocular neovascularization.Objective The purpose of this study was to explore the effect of CXCR4 antagonist on the development of cxperimental corneal neovascularization(CNV).Methods CNV model was established in the left eye of 8-weekold clean BALB/c mouse by putting the filter with 1 mol/L NaOH at the central cornea for 40 seconds.The animals were randomizcd into hyaluronate group and CXCR4 antagonist group,and the edydrops was topically administered respectively on the day of modeling 4 times per day for 14 days.CNV was examined under the slit lamp at the fourteenth day,and then the corneal suspension and section were made.Expressions of CXCR4 mRNA and protein in corneas were detected using RT-PCR and Western blot.The CD31 level in cornea was assayed by flowcytometry and immunochemistry.The expression of VEGF in burned corneas and suspension from mouse peritoneal macrophages stimulated with CXCR4 antagonist in vitro was detected by ELISA.The use of the animal followed Ragulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission.Results Two weeks after corneal alkali burn,the growth of CNV peaked under the slit lamp.Compared with hyaluronate group,CNV was obviously decreased in the CXCR4 antagonist group.Immunochemistry showed that intensity of positive staining for CD31 in cornea in the CXCR4 antagonist group was weaker than the hyaluronate group.Flowcytometry clarified that CD31 positive cells rate was 9.50％ ±2.34％ in the CXCR4 antagonist group and 17.50％ ±3.16％ in the hyaluronate group,showing a significant difference between them (t=-7.312,P＜0.05).In 2,4,7 days after cornea alkali burn,the expressions of CXCR4 mRNA and protein were significantly enhanced in burn corneas compared with normal corneas(P＜0.01 ;P＜0.05).ELISA showed that the VEGF expression level in corneal tissue and supernatant of mouse peritoneal macrophages in vitro were significantly lower in the CXCR4 antagonist group than that of hyaluronate group(t =10.927,5.151,P＜0.05).The expression level of VEGF in corneal suspension was lower in the GM-CSH+CXCR4 antogonist group than that in the GM-CSH group (P＜0.05).Conclusions CXCR4 antagonist can reduce experimental CNV by down-regulating VEGF expression in cornea.